Why do O, AS, A, AMOS, AN exist?
So that we are able to speak in personal forms, like I, you, he/she, we, and they.
What is a cation and what is an anion?
A cation is a positively charged molecule that has sucked a proton right off another molecule, while an anion is a negatively charged molecule that has sucked an electron right off another molecule, to create a (-1) negative charge.
Why are there variables in algebra?
To make you critically work out the solution, and variables give you the opportunity to check your answer to the equation!